MJDF Pharmacology & Pain Control 3 — Questions and Answers
Question 1: What class of drug is tramadol and what are its relevant side effects for dental patients?
- Atypical opioid (μ-receptor agonist + SNRI); causes nausea, dizziness, reduces seizure threshold (Correct answer)
- Pure NSAID
- Antibiotic with analgesic properties
- Antihistamine
Correct answer: Atypical opioid (μ-receptor agonist + SNRI); causes nausea, dizziness, reduces seizure threshold
Tramadol acts as a weak μ-opioid receptor agonist and inhibits serotonin/noradrenaline reuptake; dental significance includes nausea, dizziness, and interaction with serotonergic drugs risking serotonin syndrome.
Question 2: Why is aspirin contraindicated as a post-operative analgesic for dental extractions?
- Irreversibly inhibits platelet COX-1, preventing thromboxane A2 synthesis and impairing clotting for platelet lifespan (7–10 days) (Correct answer)
- Causes dry socket by direct chemical action
- Has no analgesic effect
- Causes jaw pain as a direct side effect
Correct answer: Irreversibly inhibits platelet COX-1, preventing thromboxane A2 synthesis and impairing clotting for platelet lifespan (7–10 days)
Aspirin irreversibly acetylates platelet COX-1, eliminating thromboxane A2-mediated platelet aggregation for the platelet's entire lifespan, significantly increasing post-extraction bleeding risk.
Question 3: What is the reversal agent for opioid overdose and what is its mechanism?
- Naloxone — competitive antagonist at mu, kappa, and delta opioid receptors (Correct answer)
- Flumazenil — competitive antagonist at GABA-A
- Physostigmine — acetylcholinesterase inhibitor
- Atropine — muscarinic antagonist
Correct answer: Naloxone — competitive antagonist at mu, kappa, and delta opioid receptors
Naloxone is a competitive opioid receptor antagonist that reverses respiratory depression, sedation, and other opioid effects; its short duration may require repeated doses or infusion.
Question 4: What is prilocaine's main advantage over lidocaine for dental anaesthesia?
- Lower systemic toxicity (lower CNS/cardiac toxicity), suitable for patients where adrenaline is contraindicated (used plain or with felypressin) (Correct answer)
- Faster onset
- Longer duration without vasoconstrictor
- Suitable for penicillin-allergic patients
Correct answer: Lower systemic toxicity (lower CNS/cardiac toxicity), suitable for patients where adrenaline is contraindicated (used plain or with felypressin)
Prilocaine has lower systemic toxicity than lidocaine and can be used without adrenaline (or with felypressin) for patients with cardiovascular contraindications to adrenaline, providing a safer alternative.
Question 5: What is the pharmacological difference between COX-1 and COX-2 inhibition?
- COX-1 inhibition causes GI side effects and antiplatelet effects; COX-2 inhibition is more selective for inflammatory pain with less GI toxicity (Correct answer)
- They are identical
- COX-2 causes more GI bleeding
- COX-1 is anti-inflammatory; COX-2 protects the gastric mucosa
Correct answer: COX-1 inhibition causes GI side effects and antiplatelet effects; COX-2 inhibition is more selective for inflammatory pain with less GI toxicity
COX-1 is constitutive, protecting gastric mucosa (prostaglandins maintain mucus layer) and mediating platelet aggregation; COX-2 is inducible at sites of inflammation — selective COX-2 inhibitors have fewer GI effects.
Question 6: When is chlorhexidine gluconate contraindicated in dental practice?
- Not absolutely contraindicated but should not be mixed with non-ionic surfactants (in toothpaste); avoid use immediately after brushing (Correct answer)
- Contraindicated in all patients on blood thinners
- Contraindicated in pregnancy
- Contraindicated in all periodontal patients
Correct answer: Not absolutely contraindicated but should not be mixed with non-ionic surfactants (in toothpaste); avoid use immediately after brushing
Chlorhexidine is inactivated by sodium lauryl sulphate (SLS) in toothpastes; patients should be advised to rinse with water after brushing and wait 30 minutes before using chlorhexidine mouthwash.
MJDF Pharmacology & Pain Control 3
What class of drug is tramadol and what are its relevant side effects for dental patients?